Carburetor



April 29, 1941. E. OLSON cmmmmon Filed-oat. 22. 1958 2 Sheds-Sheet 1 A Q m m e um W f l April 29, 1941. E. OLSON cmauamon Filed Oct 22. 1958 2 Sheets-Sheet 2 INVENTOR ATTORN EY Patented Apr. 29, 1941 CARBUBETOR Elmer Olson,

Detroit, Mich, assignor to George oiley and Earl Holley Application October 22, 1938, Serial No. 236,526

2 Claims;

The object of this invention is to provide a dual downdraft carburetor with a truly concentric float chamber. Additional objects are to provide such a carburetor with a common fuel orifice controlling the fuel for both mixing chambers; to prevent the fuel in the float chamber from overheating and to provide a low speed nozzle system in which the transfer from low speed operation to open throttle operation will be made smoothly and without any hesitation.

In the drawings:

Figure 1 shows diagrammatically the novel features of my invention.

Figure 2 shows a, plan view of the complete carburetor taken on plane 2-2 of Figure 3.

Figure 3 shows a cross sectional elevation taken on plane 3-3 of Figure 2.

Figure 4 shows a cross sectional elevation taken on plane 4-4 of Figure 3.

In Figure 1, A is one of the main Venturi mixing chambers; B is a small rich mixture passage which discharges into the throat of the Venturi mixing chamber A; C is a fuel chamber supplied with fuel through a restriction D which communicates with the float chamber E, which is located in the air entrance F which completely surrounds it. The air chamber F supplies air to the Venturi mixing chamber A. The fuel chamber C communicates with the small rich mixture passage 13 through the passage G. These constitute the more essential elements of my invention. A corresponding rich mixture tube BI is shown discharging into the corresponding Venturi mixing chamber Al.

In addition to the above elements, a low speed by-pass H is provided which projects into the opening G and removes from the rich mixture tube B the right mixture necessary for idling,

which rich mixture is drawn along the horizontal passage J, which communicates with a fixed outlet K and an adjustable outlet L, both discharging adjacent to the upstream lip of the butterfly M in a well known manner. The air for atomizing the rich mixture in the passage B is drawn in through the small opening N.

Considering my invention as applied to a complete carburetor, the float chamber E in Figures 2, 3 and 4 is shown as containing the standard float mechanism 0 which maintains the fuel under substantially constant level just below the level of the two openings G and G. An air entrance P is provided in which is located an ofi center choke valve Q. This, of course, is no part of this invention, nor is the acceleration fuel pump, space for which is shown at R and U in plane.

Figure 2, nor is the fuel economizer, space for which is shown at S and T. The float chamber is supported on a shoulder W which rests on a seat X.

In order to admit atmospheric pressure into the float chamber a passage V, Figure 3, is provided which acts as the float chamber vent.

Operation When idling, fuel is picked up by the tube H and passed down through the low speed passage J to the low speed fuel outlet L. After the throttle opens a little fuel is also taken in through K andfuel continues to flow through K and L although the quantity is determined by the depression existing at the opening G, so that all the fuel at low speed is by-passed around the throttle. This explains why the danger of freezing is reduced by this construction.

As the throttle opens the fuel issues directly down the rich mixture passage being aspirated by air entering through the small opening N. The rich mixture in B is diluted by the main air flow through the venturi A.

With this combination, I have discovered that the following difficulties are either eliminated or minimized:

1. Fuel flow cutting out when turning corners; 2. Vapor lock in the fuel passages due to the air cooling of the float chamber;

3. stalling during rapid deceleration.

With reference to difficulty No. 1, when turning a corner the driver of a car is notable to bank as the pilot does when turning in an air- The result is that the fuel level tilts and the fuel rises on one side of the float chamber and falls on the other, but with the construction shown the fuel level in the central chamber C within the float chamber E does not change appreciably. Hence the flow of fuel through the opening G and more particularly the flow of fuel up the passage H and down the passage J is not interrupted and remains substantially the same as when proceeding in a straight line.

With reference to difiiculty No. 2, the air flowing around the float chamber keeps the temperature of the fuel in the float chamber E below the temperature at which there will be vaporlock.

With regard to difiiculty No. 3, when releasing the clutch and applying the brake, the fuel rushes forward because of the deceleration of the car. Again, the level of the fuel in the float chamber tilts, but the level in the central chamber C does not change appreciably.

All of these difllculties are minimized by the relatively large size of the chamber C and by rounding said fuel supply chamber, two rich mixthe location of the fuel and vapor outlet G. This time passages located in the fuel supply chamchamber 0 and its outlet G are both concenher and opposit l i n d t0 each other so that trically located and the chamber c holds a suby the 9 Passages P @8011 other as closely as stantial quantity of liquid. Applicant has disa Possiblethe zone in which said Passages Pass covered that by having a considerable volume of fuel between the point ofrestriction D and the gg g g rgz' a g gg g r l D fuel and vapor outlet G, the rate of discharge g m g e 0a 0 5a of fuelis not subjected to violent variations, when 10 we] supply chamber and connected to said imthe car is accelerated, decelerated, or turned to dined rich mixture passages. the points or fuel 8 ro n 3 0011181- connection being substantially in the central What I claim is: v zone of the fuel supply chamber. 1. In a dual carburetor of the drawndraft type, 2, A device a et forth in claim 1 i whi h an air entrance, a constant level fuel supply there are'two air entrances to the two inclined chamber located substantially in the middle of rich mixture passages and these air entrances the air entrance, two relatively large air and fuel are relatively small compared with the area of mixin Ven l located below said l pp the discharge outlets from said rich mixture paschamber and symmetrically located therewith sages,

and communicating with said air entrance sur- 20 ELMER L .each other being' the central zone of said fuel sup- 

